Food slicing method and apparatus



July'7, 1 970 D, BADGLEY ET AL 3,519,051

FOOD SLICING METHOD AND APPARATUS Filed NOV. 20. 1967 DURWAED B. BADGLE Y PHIL/P C. METZLER INVENTORS ATTOR EY.

United States Patent 3,519,051 F091) SLICIN G METHOD AND APPARATUS Durward B. Badgley, Chicago, 11]., and Philip C. Metzler, Grange, Calif, assignors to Swift & Company, Chicago, 111., a corporation of Delaware Filed Nov. 20, 1967, Ser. No. 684,190 Int. Cl. A22c 17/00 US. Cl. 146222 8 Claims ABSTRACT OF THE DISCLOSURE Bacon slab thickness is continuously measured and utilized to regulate the speed of a take-off conveyor removing slices from a slicing machine. Take-01f speed is relatively increased and decreased for slices cut from deeper and shallower slabs, respectively, or portions thereof, so as to result in uniform spread of shingled slices amounting to a unit weight of product regardless of the number of slices required to produce that weight.

This invention relates to the shingling of slices as they are cut from a body of product; and more particularly relates to an improved method and apparatus for shingling variable numbers of bacon slices across a constant dimension.

Sophisticated methods and apparatus have been developed to automate the slicing of food products into drafts of substantially uniform weight. In the slicing of bacon, several methods and apparatus are known for obtaining substantially uniform weight drafts. A feed and control mechanism for producing bacon drafts of selected numbers of slices of uniform thickness is described in US. Pat. No. 3,015,350. A device for producing drafts of desired total volume (weight) of slices of equal thickness but of varying number is disclosed in U .8. Pat. No.

- 3,142,323; and apparatus for producing drafts of desired total volume (weight) comprising a selected number of slices of equal volume but varying thickness is disclosed in US. Pat. No. 3,133,571. Consumers are generally believed to prefer bacon slices of equal thickness as the cooking time for each slice is more uniform.

In most instances the bacon slices, when severed, fall from the slicer blade upon a continuously moving takeaway conveyor so as to partially overlap and shingle the slices. Slices are conventionally grouped into drafts by either interrupting the advance of the feed carriage or momentarily accelerating the speed of the take-away conveyor. The known grouping means and methods produce a uniform draft spread of slices only where the number of slices in each draft is constant.

However, because of variations in bacon slab dimensions, drafts produced by slicing systems cutting substantially uniformly thick slices have been found to require between 15 to 26 slices per pound. This variation in the number of slices has created problems in the subsequent packaging of the drafts, since it is customary to place all drafts on a card of uniform width, and where the shingling conveyor operates at a constant speed the spread of slices will vary'directly with the number thereof per draft. A 7 /2 inch wide card is standard for one-pound drafts, and it is desirable that the slices evenly cover the card.

Variations in the required number of slices per draft occur within one bacon slab as well as between slabs.

F Ice Variations are principally due to unevenness in the height or thickness of slabs. Thus one of the most efficient systerns for producing on weight drafts of slices is disclosed in the aforementioned Pat. No. 3,142,323 wherein the cross-sectional dimensions of a slab are constantly analyzed during slicing and the constant speed slicer feed is interrupted when a certain volume of slab has been sliced. This system produces slices of equal thickness but varying number per draft and results in a changing spread of slices on the package card.

Similarly with apparatus such as is shown in Pats. 3,015,350 and 3,133,571, 'where an operator must judge and select the optimum number of slices per pound to be obtained from a given slab, the number of slices selected will be changed from time to time in accordance with the range of slab thicknesses and consequently the spread of slices in the drafts will be altered.

Accordingly, it is a principal object of this invention to provide an improved method and apparatus for group'- ing slices of food products into drafts that may vary in number of slices but wherein the spread of such slices will be kept to a uniform dimension.

Another object of this invention is to provide a method and apparatus for producing bacon drafts of constant spread dimension.

A further object of this invention is to provide a method and control system for automatically varying the speed of a take-away conveyor used in conjunction with a slicing machine.

Still another object of this invention is to provide an improved method and apparatus for automatically maintaining bacon drafts of constant spread under varying conditions such as changes in bacon slab dimensions.

Generally, the present method. involves continuous measurement of the vertical dimension of a block of food product as it is fed in a given direction past a slicing knife, and generating a signal proportional to the measured dimensions. The speed of the take-away conveyor which receives the slices of food product from the slicing machine is continuously regulated as a function of this signal.

In general, the control system comprises a measuring means for continuously measuring the vertical dimension of a block of food product on the feed bed of a slicing machine, and a signal generating means connected thereto, for generating a signal proportional to the dimension, and also connected to control a variable speed drive means for continuously varying the speed of a takeaway conveyor in response to changes in the signal.

Other objects and advantages of the invention will become apparent from the following description and explanation of the invention as set forth in conjunction with the accompanying drawing wherein a bacon slicing machine embodying the present invention is shown in perspective.

The preferred method of the present invention is performed in cooperation with a volumetric analysis of the product slab being sliced, as disclosed in US. Pat. 3,142,323. However it may be adapted to any slicing technique.

A bacon slab, for example, is fed into the slicing machine at a uniform linear rate of speed and slices are severed therefrom by a blade rotated at a constant speed whereby each slice of bacon will have a uniform thickness and slices will be produced at. a uniform rate. At a point closely in advance of the slicer blade, the vertical dimension of the bacon slab is measured continuously and a signal proportional to this measured dimension is generated. In this manner, variations of the measured dimension will result in the generation of a changing signal and in all instances, even where the dimension does not vary along a slab, the signal will be proportional to the measured dimension.

The speed of the take-away conveyor is continuously regulated as a function of the signal, whereby the slices of bacon are grouped in a singled arrangement on the conveyor at a variable degree of shingle or overlap inversely related to the signal. The take-away speed is initially adjusted according to average conditions experienced with the product. An increase in bacon slab thickness (height) will produce an increased signal and consequent increased take-away conveyor speed, resulting in the relatively fewer slices being spread over a relatively greater length of conveyor; whereas a decrease in slab thickness will produce a decreased signal and consequent decreased conveyor speed to spread relatively more slices over a relatively shorter length of conveyor. In the former instance, where thicker slabs require fewer slices per pound, the slices will be overlapped to a smaller extent than in the latter instance where a greater number of slices are required for a one-pound draft.

Periodically, the feed of the slab to the slicer blade is interrupted, whereby spaced shingled groups of bacon are formed. Preferably, the time periods between the periodic interruption of the feed are automatically varied, as disclosed in the previously mentioned patents, whereby shingled drafts of bacon will be automatically segregated and spaced.

Referring to the figure, the preferred apparatus includes a plurality of sensing followers 2, such as are shown in Pat. 3,142,323, horizontally aligned above a bacon slab 4, and positioned such that the followers 2 may rise and fall with the contour of the bacon slab 4 when in contact therewith. It has been found that, for purposes of the present invention, a single follower may be regarded as representative of slab variations and the end follower has been designated to afford the required measurement of vertical dimension.

The bacon follower 2 is rigidly attached to a cam 6 so that the cam moves in a synchronous motion with the follower. In turn, a pivotally mounted cam follower 8 is mounted to rest upon the cam 6. The cam follower is connected to a signal generating means generally 10. While the latter means may comprise any of several hydraulic, electric and other devices, we prefer a pneumatic pressure generator such as is sold under the name MicroTrans by the Westinghouse Corporation, Pittsburgh, Pa. This device translates the lineal movement of a push rod 12, actuated by the cam follower 8, into a calibrated pneumatic pressure. It and other components of the pneumatic system hereinafter described are serviced by a source of air under pressure of about 60 p.s.i. (not shown) through an air supply manifold 14. Any given translational movement of the push rod 12 will cause a different p.s.i. pressure signal to be transmitted.

The pressure signal generated by the signal means is transmitted through instrumentation tubing 16 to a pressure biasing relay 18. The pressure biasing relay 18 comprises a pneumatic force-balance operation and provides an accurate 1:1 relay with manually adjustable spring bias. The biasing feature of the pressure relay 18 allows a manual setting to provide an output pressure that is a constant fixed number of p.s.i. higher or lower than the input pressure as may be required to actuate a further device. A manual biasing change may be made when changing from the slicing of one type of bacon to another. In effect, the pressure relay 18 adds the control signal received from the signal means 10 to the manual bias, and transmits this combined pressure signal.

The output pressure signal emitted from the pressure 4 biasing relay 18 is transmitted through tubing 20 and a normally open solenoid valve 22 to a volume booster 24. The volume booster 24 senses the air pressure signal received from the relay 18, and is operable to as to transmit a large volume of air at the same p.s.i., as an actuating siganl, through pipe 26 to a pneumatically powered linear actuator 28 which is operable to move an actuating rod 30 a distance proportional to the strength of the air pressure signal. Such a device is available commercially as a pneumatic valve positioner from the ConofioW Corporation of Philadelphia, Pa. The rod 30 is, in turn, connected by flexible shafting 32 to a mechanical variable speed drive means 34, powered by an electric motor 36, which drives the take-away or shingling conveyor generally 38 through a gear reducer 40 and chain 42.

The solenoid valve 22 is opened when slicing of a bacon slab 4 begins, and is closed after a slab 4 has been sliced and until a new slab is inserted. Closing of the solenoid valve 22 during the non-slicing phase of the operation serves to lock an air pressure signal in the system thus maintaining the position of actuator 28, and the takeaway conveyor 38 speed, until a new slab is located beneath the sensing followers 2.

In operation, considering an increase in the bacon slab thickness, the sensing follower 2 moves vertically upward, causing the cam '6 to depress the cam follower 8. The cam follower 8 depresses the push rod feeler 12 causing an increase in the signal means 10 control signal. This signal passes to the actuator 30 through the pressure relay 18 and booster 24. The actuator 30 then appropriately adjusts the speed control of motor 36 which speeds up the take-away conveyor 38.

Obviously many modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are in dicated in the appended claims.

We claim:

1. An improved method of shingling equal-thickness slices of food product onto a take-away conveyor, said method comprising: horizontally conveying at a constant speed into a slicer a block of food product having a substantially uniform width; continuously measuring the height of said block of food product as it is fed into said slicer; generating a signal proportional to said food block height; and directly regulating the speed at which the equal-thickness slices are removed on a take-away conveyor as a function of said signal, whereby the degree of shingle of the slices of food product is inversely proportional to said food block height.

2. The method of claim 1 wherein the last signal produced during the processing of a first block of product is maintained until processing of a second block of product is commenced.

3. The method of claim 1 including the step of periodically interrupting the feed of said block to said slicer whereby to space drafts of slices on said take-away conveyor.

4. The method of claim 1 wherein the cross-sectional area of the food product block is continuously analyzed during slicing and the constant speed slicer feed is interrupted whenever a given volume of slab has been sliced.

5. An improved control system for shingling equalthickness slices of food product onto a take-away conveyor, said system comprising: measuring means for continuously measuring the height of a block of food product of substantially uniform width and being moved in a horizontal direction at a constant speed past a slicer blade; signal generating means connected to said measuring means for generating a signal proportional to said food block height; and a variable speed drive means for directly varying the speed of the take-away conveyor in response to said signal, whereby said equal-thickness slices are spread in a shingled arrangement on said con- 7. The system of claim 5 including a signal locking 5 means located between said signal generating means and said drive means for fixing the signal at a given value during time periods between processing of successive blocks of product.

8. The system of claim 5 wherein said signal generating means is pneumatic and wherein an actuating means is connected between said signal generating means and said drive means to receive and convert the pneumatic signal.

References Cited UNITED STATES PATENTS 3,144,893 8/1964 Dahms 14695 3,145,828 8/1964 Hawley 14694 ANDREW R. JUHASZ, Primary Examiner 10 Z. R. BILINSKY, Assistant Examiner U.S. Cl. X.R. 146-94, 158, 241 

